Molecular phenotype of a pediatric small round cell tumor.
 Molecular probes were used to characterize an unusual small round cell abdominal tumor arising from the fallopian tube of a 15-year-old girl.
 DNA and RNA extracted from the tumor and adjacent normal tissue was subjected to Southern and Northern blot analysis using a variety of different probes.
 N-myc oncogene RNA was greatly expressed in the tumor, but was not expressed in normal tissue or amplified in chromosomal DNA.
 Insulin-like growth factor II RNA was similarly overexpressed in the neoplasm, but not in normal tissue.
 While histopathologic studies could not distinguish between a neuroectodermal neoplasm and Wilms' tumor, electron microscopy and the pattern of gene expression was most consistent with Wilms' tumor.
